Appraisal Instruments



Binocular Microscope - This instrument is used to illuminate and magnify gemstones and jewelry. The gemstone or piece of jewelry is held in an easily maneuvered, spring-loaded clamp and illuminated from the top and bottom. This instrument aids in the identification of internal and superficial flaws in gemstones.

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Refractometer - This instrument measures the refractive index of a gemstone by allowing light to enter the back and then directing it to the gemstone through a convex glass. A light or shadow is then cast on a measuring scale to determine the angle of refraction.

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Polariscope - This instrument is used for examining gemstones in polarized light. A gemstone is held between to Polaroid plates, and the light transmitted through the gem is analyzed. Only gemstones with sufficient transparency can be examined with a polariscope.

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Spectroscope - This instrument forms and measures reflected light from a gemstone especially in the visible region of the electromagnetic spectrum. A gemstone is placed in front of a slit in the spectrometer, and light is directed into the stone and as a result into the spectrometer where the elements involved with the resulting color of the stone can be determined.

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Dichroscope - This instrument is used to examine crystals for dichroism or the property of exhibiting different colors by reflected or transmitted light. Light is passed through a gem into the dichroscope, which is then passed through a calcite prism that uses its double refraction to separate the two polarized rays of a dichroic gemstone.

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Ultraviolet Light (long & short wave) - This instrument is used to determine the fluorescence and phosphorescence of a gemstone using short wave and long wave radiation. The gemstone is placed under the light to determine its properties.

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Leveridge Gauge - This instrument is used to measure the diameter and thickness of a gemstone. The gemstone is placed between the calipers to obtain the measurements.

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Metal Testing Kit - This instrument is used to test gold and silver. It consists of a black stone, which is used for taking scratch samples, and acids, which are dripped onto the scratch sample to identify the purity of the metal in question.

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Diamond Master Stones - This instrument is used to identify the color of a diamond. It consists of cubic zirconias colored from E to L, which are compared to a diamond to determine its color.

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Specific Gravity Liquids - This instrument is used to determine the weight of a gemstone. The gemstone is immersed in a high density liquid to determine its specific gravity.

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Gram Scale - This instrument is used to determine the weight of a piece of jewelry. Since carats are used to explain the weigh of a gemstone, these scales are primarily used to determine the weight of the metal in a piece of jewelry.

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Colorimeter - This instrument determines and specifies the color of diamonds.

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